The only reason to pursue a PhD is interest in the subject matter. You don't have to have all consuming passion and love but you have to be genuinely interested

The only reason to pursue a PhD is interest in the subject matter. You don't have to have all consuming passion and love but you have to be genuinely interested. Those who do it because their parents have phds or their colleagues, or they want "dr" in front of their name, in other words, for vanity, prestige or to further their career usually never do well. Either because they start at a later point in their lives, lack the dedication or drive to go beyond the call of duty. A phd is always about doing 110% of what is expected. In my field (physics), the expectation is to finish a phd within 6 years of completing your undergrad. If you have a good project or work hard 5 years is doable, 7 if you are a good student but got unlucky. This means the average age out of graduate school is between 26-31, depending on what country you received your undergraduate in. That is more then enough time to still start a career or work on other life goals. It's when you take longer then this timeline that things start to go wrong, for both futures in academia and industry and your life and mental health in general. A mediocre phd is worse then not doing a phd and there are plenty of those around but those who do well (not exceptional geniuses by any means!), a phd will open many doors even if you do not pursue a further academic career.